While the field of psychotherapy research has advanced greatly and various treatments have been determined to be efficacious and effective, there exists almost no research on the effectiveness of the dissemination and implementation of empirically supported treatments (ESTs). A great deal of money, time, and effort is currently being expended training practitioners how to implement ESTs and there is little research to demonstrate whether these trainings are having the intended effect on either practitioner or consumer. Dialectical Behavior Therapy (DBT) is a treatment currently being disseminated and offers an opportunity to examine the effects of training. The purpose of this study is to conduct a preliminary investigation of the impact of DBT training on therapists'in-session behavior. Therapist in-session behavior s an important component to examine in implementation and dissemination research, as higher therapist fidelity to treatment has been linked to improved consumer outcomes. This study will serve as a feasibility study of measuring therapist adherence and in-session behavior in order to conduct a larger scale study. This research is relevant to the mission of the National Institute of Mental Health to reduce the burden of mental illness and behavioral disorders through research on mind, brain, and behavior and a stated priority to create improved pathways for rapid dissemination of science to mental health care and service efforts. The study will use a multiple baseline single subject design with 20 master or doctoral level therapists who enroll in a DBT Intensive Training Course. The therapists will submit weekly psychotherapy tapes of 2 clients and one tape will be randomly selected each week for DBT adherence coding to assess impact of training on therapist in-session behavior. Tape collection will begin prior to the Intensive Training Course and continue weekly until four months post completion. In addition to adherence ratings, client outcome data, therapist DBT knowledge data, and program structure data will be collected. Research on psychotherapy training is very relevant to public health given the following, (1) effective and efficacious treatments exists for a variety of mental health problems, (2) mental health consumers have a right to the appropriate treatment done effectively, (3) money, time, and effort is currently being expended on training practitioners, and (4) little research demonstrates that these trainings are having the intended effect on either practitioner or consumer outcomes to justify the expenditures.